Stereoscopic telemeter



STEREOSGOPIC TELEMETER Flleo'l. Aug. 15, 1921 Patnte Ap1z. w, 1a23.

JTE

PATENT OTTO EPPENSTEIN, OIF JENA, GERMANY, ASSIGNO'R T0 TEE FIRM OF CARL ZEISS, OF'

JENA, GERMANY.

smnmaoscomc TELEME'IER Serial No. 492,102.

(GRANT'EI) UNDER THE PROVISIONS 0F THE AGT 01 1v11 11a011 3, 1921, 41 STAT. L., 1313.

T0 all w/zom z't may 60710677L:

Be it known that I, OTTO EPPENSTEIN, a citizen of the German Empire, residing at Jena Germany, l1ave inve'nted a new and useful Stereoscopic Telemeter (for which I have filed an application in Germany January 12, 1917, Patent 298,536, and in Austria April 8, 1918), of which the following is a specification.

Thepresent invention relates to a stereoscopic telemeter, provicled with stereoseopic measuring marks, with the apparent (listance of which during the measurernent the apparent distance of the spatial image 0f the object t0 be measured,presented by the telemeter, is compared. If it be desirable t0 test such a telemeter with regard to the COI rectness 01: its indications by observing with it a pair' of marks set up near the telerneter, the distanee apart 0f these marks being equal to the base-line of the tele1neter and their conneeting line being parallel to the said base-line, and by ascertaining whether the apparent distance of the spatial image produced fr0m these two matks be the same as the apparent distance of those of the stereoscopi c measuring marks Which belongs to the rang'e value infinite, certain drawbacks Will arise. The two images of the tw0 marks produeed by the objectives 0f the telemeter (owing t0 the comparatively short dis'tance 0f these marks) Will then appear considerably behind the focal plane of the respective objective, whilst the niarks, frorn which the stereoscopic measuring marks are prodnced, (owing to the comparatively long distance of the objects to be observed with the proper use of the telemeter) must be situated in the fofcal plane 01 the respective objective. On

test of the telemeter a stereoscopie subsidia ry mark, produed from two marks Which are disposed ea ch behind the focal plane of the 'appertaining objective. With a suitable selection of the distance between these marks and the focal planes 01 the objectives, the marks Will then be situated just as far bel1i-nd the objectives as the above mentioned images 0f the marks disposed in front of the telemeter for testing it so that the source of the aforesaid drawbaeks does n0t exist any n1ore. lt is immaterial whether the marks producing the subsidiary marks are rigidly disposed at their place o1 Whether they are so disposed as to be made operative 01 inoperative. The latter case can also be realized by adjustably disposing the marks producing the measuring marks in such a way that they may be shifted by a certain amount behind the focal plane for the purpose of the above mentioned test.

It is understood that the deficiency describecl above also exists and is also rernoved by the invention in case the telerneter does n0t present -t0 the observer a number 0f marks fixed at a different apparent distance but a single stereoscopic mark, the apparent distance of which is variable.

The annexed drawing shows as a constructional example the plan elevation of the optical system 0f a telemeter eorresponding to the invention.

Behind each 0f the two objective prisms a, an objective Z) is disposed. prism system consists 0f two ridge-edged prisms c, behind eaeh 0f which a plano-parallel glass-plate ol is disposed. The fieldlens 0f each of the two oeulars is marked 6 and the eye-lens e Between the field lens and the eye-lens there is a double reflecting prism f with a rhombic chief intersection, in order to allow of adapting in a known way the distame apart of the axes of inspeetion 150 the interoeulm distance of the observer. Thefront each of the glass plates d coincides with the focal plane of the ap* pertaining objective. Bach 0f the glass plates contains on its front a number of marks (Z which along with those of the other glass plate produce with binocular observati-on a number of stereoscopic marks, serving The ocular-* 1 two marks d produce with binofzular observation the subsidiary mark, serving for the test of the telemeter.

I claim:

In a stereoscopic telemetercontaining two objectives, stereoscopic measuring maiks arranged in the foca1 lanes of the said objectives and tWo oculars for observing both the object, the distance of which is to be measured, and the measuring marks, and

OTTO EPPENSTEIN.

Witt1esses PAUL KRGER, RICHARD HAHN. 

